Fix URLs like /projects/subproject from 404ing when they don't end with a slash

This was hit by users.
You can test it here: https://docs.celeryproject.org/projects/kombu

Author: ericholscher

readthedocs/proxito/tests/test_full.py

@@ -287,6 +287,7 @@ def test_versioned_no_slash(self):
             response['location'], '/en/latest/',
         )
 
+
     @mock.patch('readthedocs.proxito.views.serve.get_storage_class')
     def test_directory_indexes_readme_serving(self, storage_mock):
         self.project.versions.update(active=True, built=True)

readthedocs/proxito/tests/test_redirects.py

@@ -12,6 +12,13 @@
 )
 class RedirectTests(BaseDocServing):
 
+    def test_root_url_no_slash(self):
+        r = self.client.get('', HTTP_HOST='project.dev.readthedocs.io')
+        self.assertEqual(r.status_code, 302)
+        self.assertEqual(
+            r['Location'], 'https://project.dev.readthedocs.io/en/latest/',
+        )
+
     def test_root_url(self):
         r = self.client.get('/', HTTP_HOST='project.dev.readthedocs.io')
         self.assertEqual(r.status_code, 302)
@@ -26,6 +33,13 @@ def test_subproject_root_url(self):
             r['Location'], 'https://project.dev.readthedocs.io/projects/subproject/en/latest/',
         )
 
+    def test_subproject_root_url_no_slash(self):
+        r = self.client.get('/projects/subproject', HTTP_HOST='project.dev.readthedocs.io')
+        self.assertEqual(r.status_code, 302)
+        self.assertEqual(
+            r['Location'], 'https://project.dev.readthedocs.io/projects/subproject/en/latest/',
+        )
+
     def test_root_redirect_with_query_params(self):
         r = self.client.get('/?foo=bar', HTTP_HOST='project.dev.readthedocs.io')
         self.assertEqual(r.status_code, 302)

readthedocs/proxito/urls.py

@@ -147,7 +147,7 @@
     # (Sub)project single version
     url(
         (
-            r'^(?:projects/(?P<subproject_slug>{project_slug})/)?'
+            r'^(?:projects/(?P<subproject_slug>{project_slug})/?)?'
             r'(?P<filename>{filename_slug})$'.format(**pattern_opts)
         ),
         ServeDocs.as_view(),